Attending colleges you can't afford: In a Pew Research poll, 73 percent of Americans said college is a necessity, but people waste money when they spend thousands without considering likely job outcomes.

When worried about money, low-income people too often head to a nearby college that's cheap but has little success in graduating students or getting them employed. Good students have better alternatives. Even with low incomes, they can go to top-notch colleges anywhere in the country for the same as or less than the college down the road.

For example, a financial aid calculator online at http://mnstr.me/8J92ep shows a family of four earning $35,000 a year may have to pay only $1,000 a year at a top private college, even though the sticker price is more than $40,000. Financial aid opens doors, and a motivated student who brings a unique talent, race or academic interest to the college may be especially likely to get the aid.

What to do: Apply to at least eight public and private colleges regardless of price. Favor those that say they pay “100 percent of (financial) need.”

Turning down free money at work: Many employers will give you an extra 3 percent of pay, or more, each year if you contribute at least that amount to your company 401(k). The free money goes into your 401(k).

About half of the people in their 20s waste this opportunity, according to Aon Hewitt.

But consider a 35-year-old earning $50,000 a year. If he or she contributes 3 percent of pay to the company 401(k), the employer will throw in another 3 percent free — $1,500 the first year and more as raises kick in over 30 more years of work.

The result: About $237,000 in completely free money by the time a person retires, if the matching money has been invested in about 60 percent in stock mutual funds and 40 percent in bond funds earning an average of 8 percent a year.

What to do: Invest at least enough in your 401(k) to get the full freebie. But go beyond the 3 percent required. With a 3 percent match, a young worker should have enough at retirement if the individual invests 7 percent of pay.

Spending IRA distributions: When people are retired and reach 701/2 years old, they must take money out of their IRAs or 401(k) each year so that the government can tax it. But many make the mistake of thinking that since they had to remove the money, they need to spend it. They don't, and often, they shouldn't.

There's a rule of thumb about retirement savings: When you retire, you can take 4 percent to 5 percent of your total savings out of your nest egg the first year and spend it. So if you have $500,000 in savings, you can remove $20,000 the first year, and the next year you raise that just enough to cover inflation.

What to do: If your required distribution at 701/2 means you are going to spend too much of your nest egg, don't waste the money. Plan to live within the 4 percent rule and reinvest part of the money.

Paying high investment fees: Anyone who invests money pays fees, whether they have an IRA, 401(k), 529 college savings plans or other accounts. And while people might mourn losses in the stock market, they don't think twice about the money they waste on fees.

Consider what the research by Wake Forest University professor Edward O'Neal shows about the impact of small numbers: One mutual fund, or a financial adviser, charges you 1.4 percent in fees, or about $140, on a $10,000 investment. The other charges 0.31 percent, or about $31. After 20 years, if you average a 10 percent gain on your investment, the cheap, 0.31 percent choice will grow your money to about $63,000; the more expensive choice will leave you with just $51,000.

What to do: Bargain shop. Cheap funds, known as index funds, often perform better than pricier ones. If your 401(k) is charging you more than 1 percent, consider investing just enough to get free matching money and invest in extra cheap-fund savings through a Roth IRA.

Gail MarksJarvis is a personal finance columnist for the Chicago Tribune and author of “Saving for Retirement Without Living Like a Pauper or Winning the Lottery.” Readers may send her email at gmarksjarvistribune.com.